drivers/input/touchscreen/tsc2007.c

   1 /*
   2  * drivers/input/touchscreen/tsc2007.c
   3  *
   4  * Copyright (c) 2008 MtekVision Co., Ltd.
   5  *      Kwangwoo Lee <kwlee@mtekvision.com>
   6  *
   7  * Using code from:
   8  *  - ads7846.c
   9  *      Copyright (c) 2005 David Brownell
  10  *      Copyright (c) 2006 Nokia Corporation
  11  *  - corgi_ts.c
  12  *      Copyright (C) 2004-2005 Richard Purdie
  13  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  14  *      Copyright (C) 2002 MontaVista Software
  15  *      Copyright (C) 2004 Texas Instruments
  16  *      Copyright (C) 2005 Dirk Behme
  17  *
  18  *  This program is free software; you can redistribute it and/or modify
  19  *  it under the terms of the GNU General Public License version 2 as
  20  *  published by the Free Software Foundation.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/input.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/i2c.h>
  28 #include <linux/i2c/tsc2007.h>
  29
  30 #define TSC2007_MEASURE_TEMP0           (0x0 << 4)
  31 #define TSC2007_MEASURE_AUX             (0x2 << 4)
  32 #define TSC2007_MEASURE_TEMP1           (0x4 << 4)
  33 #define TSC2007_ACTIVATE_XN             (0x8 << 4)
  34 #define TSC2007_ACTIVATE_YN             (0x9 << 4)
  35 #define TSC2007_ACTIVATE_YP_XN          (0xa << 4)
  36 #define TSC2007_SETUP                   (0xb << 4)
  37 #define TSC2007_MEASURE_X               (0xc << 4)
  38 #define TSC2007_MEASURE_Y               (0xd << 4)
  39 #define TSC2007_MEASURE_Z1              (0xe << 4)
  40 #define TSC2007_MEASURE_Z2              (0xf << 4)
  41
  42 #define TSC2007_POWER_OFF_IRQ_EN        (0x0 << 2)
  43 #define TSC2007_ADC_ON_IRQ_DIS0         (0x1 << 2)
  44 #define TSC2007_ADC_OFF_IRQ_EN          (0x2 << 2)
  45 #define TSC2007_ADC_ON_IRQ_DIS1         (0x3 << 2)
  46
  47 #define TSC2007_12BIT                   (0x0 << 1)
  48 #define TSC2007_8BIT                    (0x1 << 1)
  49
  50 #define MAX_12BIT                       ((1 << 12) - 1)
  51
  52 #define ADC_ON_12BIT    (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
  53
  54 #define READ_Y          (ADC_ON_12BIT | TSC2007_MEASURE_Y)
  55 #define READ_Z1         (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
  56 #define READ_Z2         (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
  57 #define READ_X          (ADC_ON_12BIT | TSC2007_MEASURE_X)
  58 #define PWRDOWN         (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
  59
  60 struct ts_event {
  61         u16     x;
  62         u16     y;
  63         u16     z1, z2;
  64 };
  65
  66 struct tsc2007 {
  67         struct input_dev        *input;
  68         char                    phys[32];
  69
  70         struct i2c_client       *client;
  71
  72         u16                     model;
  73         u16                     x_plate_ohms;
  74         u16                     max_rt;
  75         unsigned long           poll_delay;
  76         unsigned long           poll_period;
  77
  78         int                     irq;
  79
  80         wait_queue_head_t       wait;
  81         bool                    stopped;
  82
  83         int                     (*get_pendown_state)(void);
  84         void                    (*clear_penirq)(void);
  85 };
  86
  87 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
  88 {
  89         s32 data;
  90         u16 val;
  91
  92         data = i2c_smbus_read_word_data(tsc->client, cmd);
  93         if (data < 0) {
  94                 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
  95                 return data;
  96         }
  97
  98         /* The protocol and raw data format from i2c interface:
  99          * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
 100          * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
 101          */
 102         val = swab16(data) >> 4;
 103
 104         dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
 105
 106         return val;
 107 }
 108
 109 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
 110 {
 111         /* y- still on; turn on only y+ (and ADC) */
 112         tc->y = tsc2007_xfer(tsc, READ_Y);
 113
 114         /* turn y- off, x+ on, then leave in lowpower */
 115         tc->x = tsc2007_xfer(tsc, READ_X);
 116
 117         /* turn y+ off, x- on; we'll use formula #1 */
 118         tc->z1 = tsc2007_xfer(tsc, READ_Z1);
 119         tc->z2 = tsc2007_xfer(tsc, READ_Z2);
 120
 121         /* Prepare for next touch reading - power down ADC, enable PENIRQ */
 122         tsc2007_xfer(tsc, PWRDOWN);
 123 }
 124
 125 static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
 126 {
 127         u32 rt = 0;
 128
 129         /* range filtering */
 130         if (tc->x == MAX_12BIT)
 131                 tc->x = 0;
 132
 133         if (likely(tc->x && tc->z1)) {
 134                 /* compute touch pressure resistance using equation #1 */
 135                 rt = tc->z2 - tc->z1;
 136                 rt *= tc->x;
 137                 rt *= tsc->x_plate_ohms;
 138                 rt /= tc->z1;
 139                 rt = (rt + 2047) >> 12;
 140         }
 141
 142         return rt;
 143 }
 144
 145 static bool tsc2007_is_pen_down(struct tsc2007 *ts)
 146 {
 147         /*
 148          * NOTE: We can't rely on the pressure to determine the pen down
 149          * state, even though this controller has a pressure sensor.
 150          * The pressure value can fluctuate for quite a while after
 151          * lifting the pen and in some cases may not even settle at the
 152          * expected value.
 153          *
 154          * The only safe way to check for the pen up condition is in the
 155          * work function by reading the pen signal state (it's a GPIO
 156          * and IRQ). Unfortunately such callback is not always available,
 157          * in that case we assume that the pen is down and expect caller
 158          * to fall back on the pressure reading.
 159          */
 160
 161         if (!ts->get_pendown_state)
 162                 return true;
 163
 164         return ts->get_pendown_state();
 165 }
 166
 167 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 168 {
 169         struct tsc2007 *ts = handle;
 170         struct input_dev *input = ts->input;
 171         struct ts_event tc;
 172         u32 rt;
 173
 174         while (!ts->stopped && tsc2007_is_pen_down(ts)) {
 175
 176                 /* pen is down, continue with the measurement */
 177                 tsc2007_read_values(ts, &tc);
 178
 179                 rt = tsc2007_calculate_pressure(ts, &tc);
 180
 181                 if (rt == 0 && !ts->get_pendown_state) {
 182                         /*
 183                          * If pressure reported is 0 and we don't have
 184                          * callback to check pendown state, we have to
 185                          * assume that pen was lifted up.
 186                          */
 187                         break;
 188                 }
 189
 190                 if (rt <= ts->max_rt) {
 191                         dev_dbg(&ts->client->dev,
 192                                 "DOWN point(%4d,%4d), pressure (%4u)\n",
 193                                 tc.x, tc.y, rt);
 194
 195                         input_report_key(input, BTN_TOUCH, 1);
 196                         input_report_abs(input, ABS_X, tc.x);
 197                         input_report_abs(input, ABS_Y, tc.y);
 198                         input_report_abs(input, ABS_PRESSURE, rt);
 199
 200                         input_sync(input);
 201
 202                 } else {
 203                         /*
 204                          * Sample found inconsistent by debouncing or pressure is
 205                          * beyond the maximum. Don't report it to user space,
 206                          * repeat at least once more the measurement.
 207                          */
 208                         dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
 209                 }
 210
 211                 wait_event_timeout(ts->wait, ts->stopped,
 212                                    msecs_to_jiffies(ts->poll_period));
 213         }
 214
 215         dev_dbg(&ts->client->dev, "UP\n");
 216
 217         input_report_key(input, BTN_TOUCH, 0);
 218         input_report_abs(input, ABS_PRESSURE, 0);
 219         input_sync(input);
 220
 221         if (ts->clear_penirq)
 222                 ts->clear_penirq();
 223
 224         return IRQ_HANDLED;
 225 }
 226
 227 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
 228 {
 229         struct tsc2007 *ts = handle;
 230
 231         if (!ts->get_pendown_state || likely(ts->get_pendown_state()))
 232                 return IRQ_WAKE_THREAD;
 233
 234         if (ts->clear_penirq)
 235                 ts->clear_penirq();
 236
 237         return IRQ_HANDLED;
 238 }
 239
 240 static void tsc2007_stop(struct tsc2007 *ts)
 241 {
 242         ts->stopped = true;
 243         mb();
 244         wake_up(&ts->wait);
 245
 246         disable_irq(ts->irq);
 247 }
 248
 249 static int tsc2007_open(struct input_dev *input_dev)
 250 {
 251         struct tsc2007 *ts = input_get_drvdata(input_dev);
 252         int err;
 253
 254         ts->stopped = false;
 255         mb();
 256
 257         enable_irq(ts->irq);
 258
 259         /* Prepare for touch readings - power down ADC and enable PENIRQ */
 260         err = tsc2007_xfer(ts, PWRDOWN);
 261         if (err < 0) {
 262                 tsc2007_stop(ts);
 263                 return err;
 264         }
 265
 266         return 0;
 267 }
 268
 269 static void tsc2007_close(struct input_dev *input_dev)
 270 {
 271         struct tsc2007 *ts = input_get_drvdata(input_dev);
 272
 273         tsc2007_stop(ts);
 274 }
 275
 276 static int tsc2007_probe(struct i2c_client *client,
 277                                    const struct i2c_device_id *id)
 278 {
 279         struct tsc2007 *ts;
 280         struct tsc2007_platform_data *pdata = client->dev.platform_data;
 281         struct input_dev *input_dev;
 282         int err;
 283
 284         if (!pdata) {
 285                 dev_err(&client->dev, "platform data is required!\n");
 286                 return -EINVAL;
 287         }
 288
 289         if (!i2c_check_functionality(client->adapter,
 290                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 291                 return -EIO;
 292
 293         ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
 294         input_dev = input_allocate_device();
 295         if (!ts || !input_dev) {
 296                 err = -ENOMEM;
 297                 goto err_free_mem;
 298         }
 299
 300         ts->client = client;
 301         ts->irq = client->irq;
 302         ts->input = input_dev;
 303         init_waitqueue_head(&ts->wait);
 304
 305         ts->model             = pdata->model;
 306         ts->x_plate_ohms      = pdata->x_plate_ohms;
 307         ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
 308         ts->poll_delay        = pdata->poll_delay ? : 1;
 309         ts->poll_period       = pdata->poll_period ? : 1;
 310         ts->get_pendown_state = pdata->get_pendown_state;
 311         ts->clear_penirq      = pdata->clear_penirq;
 312
 313         if (pdata->x_plate_ohms == 0) {
 314                 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
 315                 err = -EINVAL;
 316                 goto err_free_mem;
 317         }
 318
 319         snprintf(ts->phys, sizeof(ts->phys),
 320                  "%s/input0", dev_name(&client->dev));
 321
 322         input_dev->name = "TSC2007 Touchscreen";
 323         input_dev->phys = ts->phys;
 324         input_dev->id.bustype = BUS_I2C;
 325
 326         input_dev->open = tsc2007_open;
 327         input_dev->close = tsc2007_close;
 328
 329         input_set_drvdata(input_dev, ts);
 330
 331         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 332         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 333
 334         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, pdata->fuzzx, 0);
 335         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, pdata->fuzzy, 0);
 336         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
 337                         pdata->fuzzz, 0);
 338
 339         if (pdata->init_platform_hw)
 340                 pdata->init_platform_hw();
 341
 342         err = request_threaded_irq(ts->irq, tsc2007_hard_irq, tsc2007_soft_irq,
 343                                    IRQF_ONESHOT, client->dev.driver->name, ts);
 344         if (err < 0) {
 345                 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
 346                 goto err_free_mem;
 347         }
 348
 349         tsc2007_stop(ts);
 350
 351         err = input_register_device(input_dev);
 352         if (err)
 353                 goto err_free_irq;
 354
 355         i2c_set_clientdata(client, ts);
 356
 357         return 0;
 358
 359  err_free_irq:
 360         free_irq(ts->irq, ts);
 361         if (pdata->exit_platform_hw)
 362                 pdata->exit_platform_hw();
 363  err_free_mem:
 364         input_free_device(input_dev);
 365         kfree(ts);
 366         return err;
 367 }
 368
 369 static int tsc2007_remove(struct i2c_client *client)
 370 {
 371         struct tsc2007  *ts = i2c_get_clientdata(client);
 372         struct tsc2007_platform_data *pdata = client->dev.platform_data;
 373
 374         free_irq(ts->irq, ts);
 375
 376         if (pdata->exit_platform_hw)
 377                 pdata->exit_platform_hw();
 378
 379         input_unregister_device(ts->input);
 380         kfree(ts);
 381
 382         return 0;
 383 }
 384
 385 static const struct i2c_device_id tsc2007_idtable[] = {
 386         { "tsc2007", 0 },
 387         { }
 388 };
 389
 390 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 391
 392 static struct i2c_driver tsc2007_driver = {
 393         .driver = {
 394                 .owner  = THIS_MODULE,
 395                 .name   = "tsc2007"
 396         },
 397         .id_table       = tsc2007_idtable,
 398         .probe          = tsc2007_probe,
 399         .remove         = tsc2007_remove,
 400 };
 401
 402 module_i2c_driver(tsc2007_driver);
 403
 404 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 405 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 406 MODULE_LICENSE("GPL");